Plastic containers having tubular bodies and shaped or molded heads such as toothpaste tubes and the like, are made from a variety of processes. The most common application is for the tubular body, to be positioned on a mandrel and brought into registration with a mold. The plastic material to make the shaped head is normally injected into the mold with the mandrel, punch and tubular body being brought into registration with the mold under pressure to form and seal the shaped head to one end of the tubular body.
In most instances, in the prior art, this is accomplished by means of one form of a rotary press or another. In particular, see U.S. Pat. No. 4,352,775 to Magerle; U.S. Pat. No. 3,816,585 to Edwards; U.S. Pat. No. 3,711,230 to Magerle; U.S. Pat. No. 2,999,273 to Gronemeyer; U.S. Pat. No. 3,172,933 to Flax; U.S. Pat. No. 4,834,638 to Miyahara; and U.S. Pat. No. 3,313,875 to Magerle and finally, U.S. Pat. No. 4,753,761 to Lindenberger.
The shortcoming in all of the aforesaid patents is that regardless of when the plastic material for forming the shaped head is introduced, each process requires a hesitation step wherein the mandrel and punch holding the tubular body is brought into registration with the mold and pressed into the mold in order to form the shaped head. Mass production is accomplished under these methods by using multiple mandrels and molds, but nevertheless, when each mandrel and punch holding a tubular member comes in contact with the mold, there are hesitation stops while the shaped head is formed, while the bodies are loaded and unloaded and while the mold is being pressurized.
It is Applicant's invention to eliminate this hesitation step and to continuously bring a tubular body into registration with the plastic material to form the shaped head, transfer the plastic material to one end of the tubular body and then to bring the tubular body and plastic material in registration with the mold to form the shaped head.
Applicant accomplishes this task and the elimination of the hesitation step by a plurality of heading units, each heading unit having a mandrel and punch, cutting means, and mold associated therewith, the mold, and mandrel and punch being activated by a low pressure system such that the heading unit continuously moves through the low pressure activation system, setting the shaped head and then releasing the tubular body and shaped head from the heading unit while the heading unit returns to a position to accept another tubular body and repeat the process.